A variety of machine tools have been introduced in recent years which embody the concept of "automatic tool changing". Such machines, sometimes referred to as "machining centers", function automatically (or semi-automatically) under computer or numerical control and employ a tool storage device in which the metal cutting tools to be used on a given workpiece are stored. The tools perform milling, drilling, boring, tapping, reaming, and various other metal cutting functions. All of such tools have a shank which is received within the socket of a drive spindle of the machine. Many automatic tool changing machines incorporate some type of interchange tool handling mechanism by which the tool is extracted from the tool storage device and is inserted in the machine spindle, such as that disclosed in U.S. Pat. No. 3,947,951, issued on Apr. 6, 1976. In other machines the entire tool storage device is moved to position a desired new tool in alignment with the machine spindle and the spindle itself extracts the desired tool from tool storage. Yet other arrangements are also used.
Tool adjustment, particularly fine adjustment, such as is required to account for tool bit wear and replacement in these machines is usually performed either when the tool is mounted in the machine spindle or in a separate presetting machine. Thus, such adjustment techniques suffer the disadvantages of either preventing the machine from performing cutting functions while fine adjustments are being made or requiring separate operations with separate machines.
It is a primary object of the present invention to overcome these disadvantages utilizing an apparatus for fine adjusting tools which is accurate, rugged, reliable, relatively inexpensive and easy to use on many different types of machining centers having different types of tool changing systems. A related object resides in the provision of an improved method for automatically fine adjusting tools.
The present invention takes advantage of the fact that such tool storage devices are under numerical control and necessarily must maintain each tool in an accurately predetermined position to provide automatic fine adjustment while the tool is in tool changer storage. This is accomplished utilizing a unique tool construction which incorporates novel fine adjustment means which may be remotely accessed from the back (or axially inner) end thereof, in combination with a numerically controlled powered wrench located in the tool storage area. This tool construction per se is the subject of the applicant's co-pending application entitled "PRECISION ADJUSTABLE CUTTING TOOL" filed of even date.
These and other features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.